Energy Efficiency

Energy Efficiency

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Information on how to make your home more energy-efficient, reduce utility bills, and contribute to sustainability

Resource-Efficient Home Feature: Daylighting

Every home location contains inherent natural potentials such as rainfall, winds and geothermal activity, waiting to be tapped for energy and resources. More beneficial than artificial light, daylight provides an essential nutrient, relieves sleep disorders and contributes to general health and well-being. Daylighting or daylight harvesting takes advantage of sunlight for home illumination and energy while avoiding the negative aspects of overheating and glare.

In 2019, homeowners consumed 75 billion kWh of electricity for lighting. Lighting expense can be lowered simply by dimming and switching lights off and installing more efficient light bulbs.

Incorporating natural daylight into a home design considers volume, intensity, distribution, and penetration. The challenges of daylighting include:

  • glare
  • excessive heat

Windows, skylights, and light tubes can all bring free sunlight into your home. A skylight lets light in through a glazed opening in the ceiling of the room being lit. Light tubes are flexible tubes lined with highly reflective foil and illuminate rooms that are not directly beneath the opening. 

Windows, skylights, and other openings should be designed and constructed with the angle and position of the sun in mind. North-facing windows receive cool natural light, produce little glare and little summer heat gain, thus are an effective and energy-efficient means of using natural light. South-facing windows allow winter sunlight into the home but should be sheltered from the summer sunshine with long, low-hanging eaves. East and west-facing windows may cause glare and excessive heat in the summer, and barely, if at all, heats the home during winter.

Resource-efficient homes use and maximize the completely free, natural daylight that comes in through the windows and distribute it effectively into the home, when available, and as a result, homeowners avoid paying for artificial lighting.

Resource-Efficient Home Feature: Tight Building Envelope

The building envelope makes up the shell of the home. A home that has a tight building envelope means that it allows as little air leakage as possible, thus, allows for a high level of control over indoor air quality, temperature, humidity levels, and energy consumption. To you, as the homeowner, it means more comfort and less heating and cooling costs.

The components of a building envelope separate indoor and outdoor environments. Any area that is heated or air conditioned is considered a conditioned area where as any area that is not, is considered an unconditioned area. The building envelope must consider climate, ventilation, and energy consumption within the building. The envelope functions as:

  • support (resist and transfer loads)
  • control (rain, air, heat, and vapor control)
  • finish (homeowner’s taste on the outside and inside)

Construction of the building envelope requires the largest quantity of materials. It’s components are the:

  • foundation walls
  • floor slab
  • basement or crawlspace
  • exterior walls
  • windows
  • doors
  • roof

Efficient building envelope materials in new buildings can reduce upfront costs for heating, ventilation, and air conditioning (HVAC) systems.

Roofs face heat, rain, and hail; Walls contend with wind and rain; Foundations sit in wet, damp earth. What are the challenges in the construction and maintenance of the building envelope?

  • waterproofing
  • moisture control
  • drainage
  • air infiltration between the foundation, exterior walls and facade
  • insulation for the main floor

Your home’s building envelope is deemed effective if it protects you physically from weather and climate, your home has good indoor air quality, and the envelope components are durable and energy efficient.

If you have experienced leaks, mold, or excess dust in your home, you may need building envelope repair. Other signs include:

  • Water stains or damage
  • Groaning, spongy floors
  • Moldy or musty odor
  • Peeling wallpaper or paint

It is best to hire a professional when dealing with building envelope repairs or improvements as those components shield your home from the elements.

Resource-Efficient Home Feature: High R-Value

Insulation is possibly the most important element in energy-efficient homes. A home that has high R-value means that it is well insulated, thus, is more comfortable and has lower heating and cooling costs.

The “R” in R-value stands for resistance to heat flow. The higher the R-value, the more effective insulator. The amount of insulation needed depends on climate, section of the house, and type of HVAC system.

For good energy efficiency, your home may require exceeding minimum local building codes and should be properly insulated from foundation to roof.

  • basement, crawl space, or slab
  • floors above unheated garages
  • exterior walls
  • ceilings
  • ducts in unconditioned spaces
  • attic hatch and knee walls in finished attics

A home’s R-value depends on the type of insulation, thickness, density, and installation. 

What lowers the R-value?

  • gaps caused by insulation shrinkage
  • exposure to moisture from leaks or condensation
  • thermal bridging

Recommended R-values for Missouri homes:

  • Ceilings and attics: 49
  • Walls: 18
  • Floor over crawl space: 25
  • Crawl space wall: 19
  • Slab edge: 8
  • Basement wall: 11

Source: extension2.missouri.edu

Heating and cooling account for more than half of your home’s utility costs.

U. S. Department of Energy

Many older homes have less insulation than homes built today. A drafty home and high electric bills are signs that your home could benefit from insulation upgrades. Adding insulation to a home can pay for itself through energy savings within a few years. While some types of insulation may be installed by homeowners, other types require professional installation. Project costs vary depending on scope of work and whether you hire a professional. You may also find Federal tax credits to offset project costs.

Resource-Efficient Home Feature: Optimal Indoor Air Quality

The impact of air quality in our home on our health is significant. According to the Environmental Protection Agency, in the United States, on the average, we spend about 90 percent of our time indoors.

What is considered good Indoor Air Quality (IAQ)? A home is considered to have good indoor quality when there is good ventilation, appropriate temperature and humidity, is free from allergens, pathogens and other biological contaminants, free from tobacco smoke, and objectionable odors. 

Indoor climate systems impact the quality of the indoor air. If too little outdoor air enters a home, pollutants can accumulate to severe levels. It is important for homes to have a special mechanical means of ventilation to prevent pollutants from building up indoors.

We may not notice good IAQ but we will certainly notice if there is a problem with odors, fumes, or mustiness. Many factors contribute to indoor air quality like poor ventilation, occupants’ activities, and outdoor pollutants.

Indoor pollutant sources can include:

  • fuel-burning combustion appliances
  • tobacco products
  • deteriorated asbestos-containing insulation
  • newly installed flooring, upholstery or carpet
  • cabinetry or furniture made of certain pressed wood products
  • products for household cleaning and maintenance, personal care, or hobbies
  • central heating and cooling systems and humidification devices
  • excess moisture
  • radon
  • pesticides
  • outdoor air pollution

The simplest test of indoor air quality may be stepping outside your home for a few minutes. When you go back inside, what do you smell? If you smell damp, mustiness, tobacco odor, dust, fumes, pet odors, chemicals, or pesticides, your home may have an IAQ issue.

IAQ Issue: Off-Gassing

Many materials used in traditional home construction such as paint, carpet, cabinetry, adhesives, wall board, and wall coverings can emit, or off-gas, unpleasant and even toxic volatile organic compounds (VOCs) such as formaldehyde.

Off-gassing can trigger respiratory conditions such as asthma and other allergic reactions. It is also linked to multiple chemical sensitivity syndrome. When new carpet, paint, or cabinets are off-gassing, keep air flowing throughout the home until the odor dissipates.

IAQ Issue: Lead Paint

Found in some older homes, lead paint has serious health consequences for both children and adults if ingested as chips, dust or in drinking water. Exposure can impair brain and nervous system development and stunt growth of children, and hypertension, reproductive problems, memory and cognitive impairment, and other conditions to adults.

Lead test kits help detect the presence of lead. When lead is detected, the EPA strongly recommends additional testing, and risk assessment by a certified lead inspector or a certified lead risk assessor. Consider hiring professional contractors who are experienced in removing lead paint safely.

*Federal law requires that contractors performing renovation, repair, and painting projects that disturb more than six square feet of lead paint in homes must be trained and certified to follow specific work practices to prevent lead contamination.

IAQ Issue: Asbestos

Once commonly used in building materials, asbestos, when inhaled is linked to lung cancer and pulmonary disease. An inspection by a qualified asbestos professional is always required because materials with asbestos cannot be identified by sight. Repair options include:

  • encapsulation (sealing)
  • enclosure (covering)
  • removal
*An asbestos professional should be hired if the material must be repaired or removed.

IAQ Issue: Mold

Mold grows in places that are always damp, and can be seen and smelled. They produce allergen irritants which can be toxic. If you suspect that there is hidden mold in your home, you should consider hiring an experienced professional. Removal of drywall or wallpaper can lead to a massive release of spores growing on the underside.

*Avoid touching or inhaling mold or mold spores during cleanups. 

IAQ Issue: Radon

Radon, a radioactive gas, is associated with lung cancer. It is the result of the breakdown of uranium in soil and emitted into the air, water, and soil and can seep into any type of building through cracks in basement and crawlspace walls, or through well water. Radon test kits are available and should be used if a homeowner plans to finish a basement to convert it into living space. Solutions include soil suction, barriers and venting.

*A radon-mitigation professional can help in lowering radon levels.

IAQ Issue: Harmful Combustion Gases and Particulates

Blocked, leaking, or damaged chimneys, flues, and ducts release gases and particles and even fatal concentrations of carbon monoxide. Particles can lodge in the lungs and damage lung tissue. Safety precautions include:

  • annual HVAC inspections including flues, ducts, and chimneys
  • prompt repair of cracks or damaged parts of HVAC systems
  • regular inspection of wood stoves and vents
  • use of only aged or cured (dried) wood in stoves and fireplaces (NOT pressure-treated wood)

Good information to know:

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